Mono azo dyes



United States Patent 3,186,982 MONO AZO DYES Milton Green, Newton enter, and Howard G. Rogers,

Weston, Mass, assignors to Polaroid Corporation, Cambridge, Mass, a corporation of Delaware .No Drawing. Filed Apr. 27, 1962, Ser. No. 190,864

4 (Claims. (Ci. 26ii202) This application is in part a continuation of our copending application, Serial No. 748,145, filed July 14, 1958 This invention relates to photography and more particularly to products, compositions and processes for the development of photosensitive silver halide elements.

It is one object of the present invention to provide novel processes and compositions for the development of silver halide emulsions, in which colored developing agents are used to develop a latent image.

Another object is to provide novel processes and compositions for the development of silver halide emulsions, in which the novel developing agent is capable of developing a latent image and imparting a reversed or positive colored image of said latent image to a superposed imagereceiving material.

Still another object is to provide novel products, processes and compositions suitable for use in preparing monochromatic and multichromatic photographic images.

A further object is to provide novel compounds which are useful as intermediates and color-providing materials.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the processes involving the several steps and the relation and order of one or more of such steps with respect to each of the others, and the products and compositions possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

The novel photographic developing agents, i.e., the novel dihydroxyphenyl compounds, employed in this in vention possess the properties of both dye and a develop ing agent; thus they may be referred to as dye developers. The nature of these dye developers will be described hereinafter.

The photographic processes and compositions disclosed herein are particularly useful in the treatment of a latent image present in a photosensitive element, such as an exposed silver halide emulsion, whereby a positive dye image thereof may be imparted to another element, herein referred to as an image-carrying or image-receiving element.

US. Patent No. 2,983,606, issued May 9, 1961, discloses diffusion transfer-reversal processes wherein a photographic negative material, such as a photographic element comprising an exposed silver halide emulsion layer containing a latent image, is processed to impart to an image-receiving element a reversed or positive dye image of said latent image by permeating into said emulsion layer a suitable liquid processing composition and bringing said emulsion layer into superposed relationship with an appropriate image-receiving layer. It is an object of this invention to provide additional dye developers suitable for use in such processes.

In carrying out the process of this invention, a photosensitive element containing a silver halide emulsion is exposed and wetted with a liquid processing composition, for example, by immersing, coating, spraying, flowing, etc., in the dark, and the photosensitive element superposed, prior to, during or after wetting, on a sheetlike support element, which may be utilized as an image-receiving 3,i36,82 Patented June 1, 1965 element. In a preferred embodiment, the photosensitive element contains a layer of dye developer, and the liquid processing composition is applied to the photosensitive element in a uniform layer as the photosensitive element is brought into superposed position with an image-receiving element. It is also within the scope of this invention to apply the liquid processing composition prior to exposure, in accordance with the disclosure in the copending application of Edwin H. Land, Serial No. 498,672, filed April 1, 1955 (now US. Patent No. 3,087,816, issued April 30, 1963). The liquid processing composition permeates the emulsion to provide a solution of dye developer substantially uniformly distributed therein. As the latent image is developed, the oxidation product of the dye developer is immobilized or precipitated in situ with the developed silver, thereby providing an imagewise distribution of unoxidized dye developer dissolved in the liquid processing composition. This immobilization is apparently, at least in part, due to a change in the solubility characteristics of the dye developer upon oxidation, and especially as regards its solubility in alkaline solutions. It may be also due in part, to a tanning effect on the emulsion by the oxidized developing agent. At least part of this imagewise distribution of unoxidized dye developer is transferred, by imbibition, to a superposed image-receiving layer or element, said transfer substantially excluding silver or oxidized dye developer. Under certain circumstances, the layer of the liquid processing composition may be utilized as the image-receiving layer. The latter element receives a depthwise diffusion, from the emulsion, of unoxidized dye developer Without appreciably disturbing the imagewise distribution thereof to provide a reversed or positive, colored image of the developed image. The image-receiving element may contain agents adapted to mordant or otherwise fix the diffused, unoxidized dye developer. If the color of the diffused dye developer is aifected by changes in the pH of the image-receiving element, this pH may be adjusted in accordance with well-known techniques to provide a pH affording the desired color. Imbibition periods of approximately one minute'have been found to give good results, but this contact period may be adjusted where necessary to compensate for variations in temperature or other conditions. The desired positive image is revealed by stripping the image-receiving element from the photosensitive element at the end of the imbibition period.

The dye developers of this invention may be utilized in the photosensitive element, for example in, on or behind the silver halide emulsion, or they may be utilized in the image-receiving element or in the liquid processing composition. In a preferred embodiment, a coating or layer of the dye developer is placed behind the silver halide emulsion, i.e., on the side of the emulsion adapted to be located most distant from the photographed subject when the emulsion is exposed and preferably also adapted to be most distant from the image-receiving element when in superposed relationship therewith. Placing the dye developer behind the emulsion layer, as in the preferred embodiment, has the advantage of providing increased contrast in the positive image, and also minimizes any light-filtering action by the colored dye developer. In this preferred embodiment, the layer of dye developer may be applied by using a coating solution containing about 0.5 to 8%, by weight, of the dye developer. Similar concentrations may be used if the dye developer is utilized as a component of the liquid processing composition, concentrations as low as 0.2% in the liquid processing composition being suitable in certain instances.

The liquid processing composition above referred to comprises at least an aqueous solution of an alkaline compound, for example, diethylam-ine, sodium hydroxide or sodium carbonate, and may contain the dye developer.

, 3 I In some instances, it may contain an auxiliary or accelerating developing agent. If the liquid processing composition is to be applied to the emulsion by being spread thereon, preferably in a relatively thin, uniform layer, it may also include'a viscosity-increasing compound comprising a film-forming materialof the type which, when said composition is spread and dried, will form a relatively firm and relatively stable film. A preferred filmforming material is a high molecular weight polymer such as a polymeric, water-soluble ether inert to an alkali solution, as, for example, hydr-oxyethyl cellulose or so dium carb-oxymethyl cellulose. Other film-forming materials or thickening agents whose ability to increase viscosity i substantially unaffected when left in solution for a long period oftime may also be used. r

The novel compounds of th' invention may be represented by the formula:

, x Y-)m 11 I-ii-z -N=N-Ar -N=N-Ar wherein X is an aryl group selected from the group consisting of benzene and naphthalene radicals so substituted by at least two groups selected from the group consisting of hydroxyl and amino groups as to be capable of develop ing an exposed silver halide photographic emulsion; Y is a divalent organic linking radical; R is hydrogen or a lower alkyl group, such as methyl, ethyl, propyl, etc.; n is 1 or 2; m is 1 or 2; Z is a divalent aromatic orheterocyclic group; Ar is a monovalent aromatic or heterocyclic group; and Ar is'a monovalent aromatic or heterocyclic group, when n is 1, or a divalent aromatic or heterocyclic group, when n is 2.

As examples of typical aromatic and heterocyclic groups, signified by the respective terms Z, Ar and Ar in Formula A, suitable for use in the practice of this invention, mention may be made of substituted and unsubstituted aromatic and heterocyclic groups of the pyrazolone,

benzene and naphthalene series. a p

' Examples of radicals which may be present in such substituted groups include alkyl, sulfo, alkoxy, aryl, arylfoxy, amino, keto, alkylamino, arylamino, hydroxyl, cyano,

alkylamido, arylamido, carboalkoxy, car-boxamido, sulfonamido', etc.

I The preferred group of compounds of the'present invention may be represented by the formula:

wherein X represents a p-dihydroxyphenyl or an o-dihydroxyphenyl group; R represents hydrogen or a lower alkyl group comprising from 1 to 5 carbon atoms, inclusive; Y represents a divalent hydrocarbon group which is an alkylene, a phenylene, or a phenalkylene group wherein the al-kylene radical is a lower alkylene radical;

m is 1 or 2; Z is an arylene group of the benzene or nap-h thalene series having the carbon atom of the carbonyl group directly attached to a first cyclic carbon atom and a first nitrogen atom of the azo group (N=N,) directly attached to a second cyclic carbon atom; Ar is a monovalent cyclic group of the benzene, naphthalene or pyrazolone series having the second nitrogen atom of the azo group (-N=N) directly attached to a cyclic carbon atom; and either Z or AI has a hydroxyl or amino directing group directly attached to a cyclic carbon atom in either ortho or para position with regard to the azo group (N=N). As examples of divalent radicals, signified by the term Y in Formula A, suitable for use in the practice of this invention, mention may be made of; preferred divalent hydrocarbon radicals such as, e.g., alkylene radicals, p-ref 'erably lower alkylene radicals comprising from 1 to 5 carbon atoms, inclusive, such as ethylene, isopropylene,

7 i etc.; arylene radicals, such as phenylene, etc.; and alkaryh ene radicals, such as phenethylene; acyl radicals such as 3 V V C -alkyleneetc; and divalent organic radicals which contain both hetero and carbon atoms as constituent components of said radicals, such as, e.g.,

be capable of developing an exposed silver halide emulsion, that is, benzene and naphthalene nuclei substituted by at least two hydroxyl and/ or amino groups, one of said groups substituted in one of ortho and para positions with respect to one other of said groups. The preferred silver :halide developing groups comprise dihydroxyphenyl groups, and specifically p-dihydroxyphenyl and o-dihydroxyphenyl groups, and the ubstituted derivatives of such groups as, for example, nuclear substituted alkyl and halogen derivatives. Other suitable developing groups include orthoand para-amino-substit-uted hydroxyphenyl groups. In general, the developing group comprises a benzenoid developing configuration, that is, an aromatic developing group which forms quinonoidor quinone products upon oxidation.

wherein X m; Y and R have the same significance as previously noted; such as, for example;

Amino-ethyl-hydroquinone, the preparation of which is disclosed in the copending U.S. application of Milton Green, Serial No. 514,095, filed June 8, 1955 now U.S. Patent No. 3,062,884, issued November 6, 1962;

Amino-phenethyl-hydroquinone, the preparation of which is disclosed in U.S. Patent No, 3,019,107, issued lannuary 30, 1962;

Amino-phenethyl-thio-Vhydroquinone, the preparation of which is disclosed in U.S. Patent No. 3,009,95 8, issued November 21, 1961;

Amino-phenoXy-hydroquinone, the preparation of which is disclosed in the copendingUS, application of Milton Green and Warren E. Solodar, Serial No. 680,406, filed August 26, 1957, now U.S. Patent No. 3,061,434, issued October 30, 1962; 7 r

Amino-hydroquinone, amino-phenyl-hydroquinone, and

amino-phenyl-sulfonyl-hydroquinone, the catechol analogues, and corresponding secondary amines wherein R is an alkyl group, etc., which may be prepared by known chemical reactions;

with a compound of the formula:

wherein Z, Ar, Ar and n have the same significance as previously'noted; such as, for example: 7

4- 1'-hydroxy-4'-rnethoxy-2'-naphthaleneazo -benzoyl chloride; V V.

4-(4-aminol'-hydroxy 2-napthaleneazo)-benzoyl chloride; r

4- 1'-hydroxy-4'-n-propxy-2'-naphthaleneazo -benzyl chloride;

4- (4'-acetamido-1'-hydroXy-2'-naphthaleneazo)-benzoyl chloride;

4 -aminol -hydroxy -napthalene azo -benzoyl chloride;

4- l ',5-diamino-4-naphthaleneazo -benzoyl chloride;

4-(2-amino-1-naphthaleneazo )-benzoyl chloride;

4- (4'- cyclohexyloxyl'-hydroXy-2'-naphthaleneazo benzoyl chloride;

4-(4-hexyloxy-1'-hydroXy-2naphthaleneazo)-benzoyl chloride;

4- 1'-hydroxy-4-isoprop0Xy-2-napthaleneazo -benzoyl chloride;

4- 5 -benzamido-1 '-hydroxy-2'-naphthaleneazo) -benzoyl chloride;

4-( 1'-hydroxy-4'-sulfo-2'-naphthaleueazo -benzoyl chloride;

4-(5'-acetamido-1-hydroxy-2'-naphthaleneazo)-benzoyl chloride;

4- (2-hydroxy-1'-naphthaleneazo)-benzoyl chloride;

4- 3 '-rnethyl-1-phenyl-5-pyrazoloneazo-4)-benzoyl chloride;

4- 1 ,3 '-diphenyl-5-pyrazoloneazo-4 -benzoyl chloride;

4- 3-N-cyclohexylcarboxamido-1'-phenyl5-pyrazoloneazo-4')benzoyl chloride;

4- (3 '-amino-l'-phenyl-5 -pyrazoloneazo-4' -benzoyl chloride;

4- (3-diphenylacetamido-1'-phenyl-5'-pyrazoloneazo- 4' -b enzoyl chloride;

4- (3 -carbethoxy l '-phenyl-5'-pyrazolone azo-4 benzoyl chloride;

4- (3'-N-n-butylcarboxamido-1'phenyl-5-pyrazoloneazo-4)-benzoyl chloride; etc.

Another method of preparing the novel compounds of this invention comprises reacting, in the presence of a suitable halogen acid acceptor, a compound of Formula D with a compound of the formula:

X?- (Y) m-;A H wherein X is an o-bis-acyloxyphenyl or a p-bis-acyloxyphenyl group and alkyl and halogen substituted derivatives thereof and in, Y and R have the same significance as previously noted.

The compounds of Formula E may be prepared by the selective acylation of the compounds of Formula C according to the procedure disclosed in US. Patent No. 3,019,254, issued January 30, 1962.

After reaction and prior to use as a photographic dye developer, the acyloxy groups may be removed by deesterification, as for example, by hydrolysis in the presence of alkali.

Still another method of preparing the novel compounds of this invention comprises coupling a diazonium derivative of a compound of the formula:

(F (Ar N=N) ArNH with a compound of the formula:

(G) I ll X -(Y)m-1NC-Z wherein Z is an aryl group substituted by a hydroxyl or amino group; Ar, Ar n, m, Y and R have the same significance as previously denoted; and X represents the protected derivatives of a benzenoid silver halide develop ing group selected from the group consisting of benzene and naphthalene nuclei so substituted by at least two groups selected from the group consisting of hydroxyl and amino groups as to be capable of developing an exposed silver halide emulsion, as, for example, the ester derivatives thereof.

The protective groups may be removed subsequent to reaction, for example, by hydrolysis in the presence of alkali.

A preferred compound within Formula B is:

on on it CHrCHr -Nu-o-@N N (H) 2-(4-[4-(2"',5"'-dihydroxyphenethyl) phenylcarba1nyl1-phenylazo) 4-methoXy-1-naphthol As examples of other dye developers within the scope of Formula B, mention may be made of:

CMH NJ limos Another group of preferred novel compounds which may be used to accomplish the objects of this invention may be represented by the formula:

( l g I wherein Z is an arylene group substituted by a hydroxyl group ortho to the carboxamido group; and X, R, Y, m and Ar have the same significance as previously denoted. It should be understood that, as previously stated, the definition of Ar as aryl is intended to include a substituted aryl groups, and suitable suhstituents include halogen, nitro, alkylamino, arylarnino, sulfo, etc. The azo group is attached to the same aryl nucleus as the carboxamido group.

A preferred group of dye developers with the scope of Formula L may be represented by the formula:

wherein Ar, m and Y have the same meaning as above; each A may be hydrogen, alkyl or halogen; and p is 0 or a positive integer from 1 to 3, inclusive.

(N) 1-(2,5-dimetl1oXy-4'-methyl-phenylazo) 3 (2',5'-

dihydroxyphenethylcarbamyl)-2-naphthol (O) 3-(2',5-dihydroxyphenethylcarbamyl) 1 (2' methoxy-4-methyl-phenylazo)-2-naphthol resultant precipitate with water.

aisaese (P) 3-(2,5-dihydroxyphenyltrimethylcarbamyl) 1 (2'- methoxy-4'-methylphenylazo)-2-naphthol (Q) 3-(2',5'-dihydroxyphenylcarbamyl)-1-(2' methoxy- 4'-methyl-phenylazo) -2-naphthol ever are not limited to the details therein set forth and i are intended to be illustrative only.

Example I A mixture of 1,7 g; (0.005 mole) of 4-(l-hydroxy- 4- methoxy-2' -naphthaleneazo)-benzoyl chloride (prepared by coupling diazotized p-aminobenzoic acid into 4-methoxy-1-naphthol and reacting the resultant product thereof with phosphorous pentichloride) and 1.9 g. (0.005 mole) of p-aminophenethyl-hydroquinone-0,0-diacetate hydrochloride in 50 cc. of anhydrous pyridine is warmed gently on a steam bath in a nitrogen atmosphere for 45 minutes. The mixture is then poured into a dilute hydrochloric acid solution and the resulting slurry filtered. The filter cake is washed with a dilute hydrochloric acid solution and then washed with Water yielding 2.0 g. of 2-(4'- [4" (2"',5" diacetoxyphenethyl) phenylcarbamayl} phenylazo)-4-methoxy-l-naphthol.

Example 2 2.0 g. of 2-(4-[4"-(2"',5"'-diacetoxyphenethyl)-phenylcarbamayH-phenylazo) 4 methoxy 1 naphthol are treated in vacuo with a mixture of 3 g. of potassium hydroxide, 40 cc. of ethanol and 20 cc. of Water with intermittent warming of a steam bath for 3 minutes. The product is precipitated with a dilute hydrochloric acid solution, the resultant slurry filtered and the filter cake washed with water. The dye developer is further purified by dissolving it in acetic acid, precipitating with water and washing the A yield of 0.6 g. (dry weight) of 2- (4- [4"- (2"',5"'-dihydroxyphenethyl) -phenethyl)-pheny1carbamyl] -phenylazo)-4-methoxy 1 naphthol, [Formula H], is obtained which decomposes at 200 C.

Analysis of this product:

C, H, N, percent percent percent Calculated 72. 1 5. 06 7. 88 Found s9. 6 5. s. 0

A solution of 0.38 g. of dimethoxy aniline in 1.2 cc. of 6 N. HCl cooled to 0 C. and diazotized by the addition 'of 0.18 g. of sodium nitrite in 0.5 get water. The diazotized product is then added slowly at C. to 1. g. of a 8 monobenzoate of 2-l'1ydroxy-N-(2',5-dihydroxyphenyl)-3- naphthamide dissolved in 50 cc. of ethanol, 25 cc. of acetone and 50 drops of pyridine. sodium carbonate are then added and the solution stirred for thirty minutes during which time a precipitate forms. The precipitate is collected and hydrolyzed by dissolving in 2.0 cc. of 50% aqueous ethanol and adding 4 g. of sodium hydroxide dissolved in 6 cc. of water. The mixture is allowed to stand for an hour under vacuum and then filtered quickly. The filtrate is acidified and cooled to give a precipitate of 1 g. of a compound having the formula:

OCHa

' (1)13: .QCHa.

OH I

l- (2 ,5'din1ethoxyphenylaz0) '3- 2,5-dihydroxyphenyl- V carbamyl) -2-napl1tho1 Analysis of this product:

C, H, N. percent percent percent 65.4 4. 57 9.14 Found. 64. 9 4. 7 9.1

carriedrout in the absence of actinic radiation. These examples are intended to be illustrative only of the photographic use of the dye developers and should not be construed as limiting the invention in any way..

Example 4 V i A photosensitive element is prepared by coating a gelatin-coated film base with a solution containing 4% of 2- (4'-[4" (2",5" dihydroxyphenyl) phenylcarbamyllphenylazo)-4-methoxy-1-naphthol, [Formula H as prepared in Example 2], in a 4% solution of cellulose acetate hydrogen phthalate in a 50:50 mixture, by volume, of

Sodium carboxymethyl cellulose "a 4.5

1-pl1enyl-3-pyrazolidone '0.2 a I Sodium hydroxide 2.5

Potassium bromide 0.2

acetone and tetrahydr ofuran. After this coating has dried, a silver iodobromide emulsion is applied. This photosensitive element is exposed and processed by spreading an aqueous liquid processing composition comprising:

' 7 Percent between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The image-receiving element comprises a cellulose acetate-coated baryta paper which has been coated with a solution comprising 4% Nylon Type F8 (N-m'ethoxymethyl polyhexamethylene adipamide) in aqueous ethanol. After an imbibition period of approximately one minute, the'image-receiving element is image of the photographed subject. 5

Twenty drops of 25% 9 Example A photosensitive element is prepared by coating 2 baryta base with a solution of 1.6 g. of the dye developer prepared in Example 3 dissolved in 100 cc. of a solution comprising:

Cellulose acetate hydrogen phthalate g 4 Acetone cc 80 Methanol cc 2O Ethyl cellosolve (ethylene glycol monoethyl ether) cc 1 After this coating has dried, a silver halide emulsion is applied and allowed to dry. An image-receiving element is prepared by coating a polyvinyl butyral-coated baryta base with a solution comprising 4 g. of Nylon Type F8 in 20 cc. of water and 80 cc. of isopropanol. The photosensitive element is exposed and a liquid processing composition comprising:

Water cc 100 Sodium hydroxide g 1.5 Phenyl ethanol cc 1.5 Metal (N-methyl-p-aminophenol) g 0.2 Sodium carboxymethyl cellulose g 4.0

is applied to the exposed photosensitive element as that element is brought into superposed relationship with the above-described image-receiving element. After an imbibition period of approximately one minute, the imagereceiving element is separated and contains a pink-purple positive dye image of the photographed subject.

It is also possible to employ a composite film unit comprising an image-receiving layer and a photosensitive or emulsion layer so arranged that the liquid processing composition must permeate through the emulsion layer before reaching the image-receiving layer. In this embodiment, the liquid processing composition is applied to the emulsion layer as the composite film unit is brought into superposed relationship with a relatively impermeable, backing or spreading element. The emulsion layer is so formed that it may be readily separated from the image-receiving layer. Thus, for example, when the image-receiving layer is separated upon the completion of the imbibition period, the emulsion layer adheres to and is retained with the spreading element. An example of such a composite film unit is given in U.S. Patent No. 2,661,293, issued to Edwin H. Land on December 1, 1953. Note, in particular, FIGURE 7 of the drawing of said patent.

The following example is given to illustrate the use of the dye developer as a component of the liquid processing composition and also to illustrate the use of a composite film unit such as just described.

Example 6 An image-receiving layer is prepared by coating a polyvinyl butyral-coated baryta base with a solution of 4 g. of Nylon Type F8 in 80 cc. of isopropanol and 20 cc. of water. After the nylon coating has dried, a silver halide emulsion layer is applied thereto. A liquid processing composition is prepared comprising:

Water cc 100 Sodium carboxymethyl cellulose g 4.5 Sodium hydroxide g 1.5 1-(4'-benzamido 2',5' diethoxy) phenylazo 3- (2',5-dihydroXyphenylcarbamyl-Z-naphthol g 2.0 Sodium carbonate g 2.0 Sodium suliite g 0.1 Dimethyi-formamide cc 20 The dye developer referred to above is prepared in a manner similar to that set forth in Example 3 and has the formula:

The composite image-receiving and emulsion-containing element is exposed and the liquid processing composition applied'thereto as this element is brought into superposed relationship with a spreading sheet or element. After an imbibition period of approximately one minute, the image-receiving layer is separated and is found to contain a blue-purple positive dye image of the photographed subject.

It will (be noted that the liquid processing composition may, and in the above examples does, contain an auxiliary or accelerating developing agent, such as p-methylaminophenol, 2,4-diaminophenol, p benzylaminophenol, hydroquinone, toluhydroquinone, phenylhydroqu-inone, 4-methylpheuythydroquinone, etc. A preferred accelerating developing agent is a 3-pyrazolidone developing agent and preferably 1-phenyl-3-pyrazolidone. It is also contemplated to employ a plurality of auxiliary or accelerating developing agents, such as a 3-pyrazolidone developing agent and a benzenoid developing agent, as disclosed and claimed in the copending application of Howard G. Rogers and Harriet W. Lutes, Serial No. 654,781, filed April 24, 1957 (now US. Patent No. 3,039,869). As examples of suitable combinations of auxiliary developing agents, mention may be made of lphenyl-3-pyrazolidone in combination with p-benzylaminophenol and 1-phenol-3-pyrazolidone in combination with 2,5-1bis-ethylenimino hydroquinone. Such auxiliary developing agents may be employed in the liquid processing composition or they may be initially incorporated, at least in part, in the silver halide emulsion strata or the strata containing the dye developers. It may be noted that at least a portion of the dye developer oxidized during development may be oxidized and immobilized as a result of a reaction, e.g., an energy-transfer reaction, with the oxidation product of an oxidized auxiliary developing agent, the latter developing agent being oxidized by the development of exposed silver halide. Such a reaction of oxidized developing agent with unoxidized dye developer would regenerate the auxiliary developing agent for further reaction with the exposed silver halide.

In addition, development may be effected in the presence of an onium compound, particularly a quaternary ammonium com-pound, in accordance with the processes disclosed an claimed in the copending U.S application of Milton Green and Howard G. Rogers, Serial No. 50,851, filed August 22, 1960.

The dye developers of this invention may the used also in conventional photographic processes, such as tray or tank development of conventional photosensitive films, plates or papers to obtain black-and-white, monochromatic or toned prints or negatives. By way of example, a developer composition suitable for such use may comprise an aqueous solution of approximately 1 to 2% of the dye developer, 1% sodium hydroxide, 2% sodium sulfite and 0.05% potassium bromide. After development is completed, any unreacted dye developer is washed out of the photosensitive element, preferably with an alkaline washing medium or other medium in which the unreacted dye developer is soluble. The express-ion toned is used to designate photographic images wherein the silver is retained with the precipitated dye, whereas monochromatic is intended to designate dye images free of silver.

It should be noted that the dye developers of this masses image and do not depend upon coupling reactions to produce the desired color. They thus provide a complete departure from conventional photographic color processes in which the color is produced by a coupling reaction involving the oxidized developing agent.

It should be noted that it is within the scope of this invention to use mixtures of dye developers to obtain a desired color.

It will be apparent that, by appropriate selection of the image-receiving element from among suitable known opaque and transparent materials, it is possible to obtain either a colored positive reflection print or a colored positive transparency.

As examples of useful image-receiving materials, mention maybe made of nylon such as N-methoxymethy1 polyhexamethylene adiparnide; partially hydrolyzed polyvinyl acetate; polyvinyl alcohol with or without plasticizers; baryta paper, i.e., a support having a baryta coating thereon; cellulose acetate with filler .as, for example, one-half cellulose acetate and one-half oleic acid; gelatin; and other materials of a similar nature, as is well known in the art. Preferred materials comprise polyvinyl alcohol or gelatin containing a dye mordant such as poly.

' 4-vinylpyridine, as disclosed and claimed in the copending US. application of Howard C, Haas, Serial No. 50,848, filed August 22, 1960 (now U.S. Patent No. 3,148,061, issued September 8, 1964). V

The inventive concepts herein set forth are also adapt able for multicolor work by the use of special photographic materials, for example, film materials of the type containing two or more photosensitized elements associated with an appropriate number of image-receiving elements and adapted to be treated with one or more liquid processing compositions, appropriate dye developers suitable to impart the desired subtractive colors being incorporated in the photosensitized elements or in the liquid processing compositions. Examples of such photographic materials are disclosed in US. Patent No. 2,647,049, to Edwin H. Land.

The inventive concepts herein set forth are also adaptable for the formation of colored images in accordance with the photographic products and processes described in US. Patent No. 2,968,554, issued January 17, 196 1, and also the copending application of'Edwin H. Land and Howard G. Rogers, Serial No. 565,135, filed February 13, 1956.

In the preceding portions of the specification the eX- pression color has been frequently used. This expression is intended to include the use of a plurality of colors to obtain black, as well as the use of a single black dye developer. 7

Our copending US. application, Serial No. 748,146,

12 1 graphic ultization of the novel compounds of the present invention, especially in difiusi'on-transfer' reversal processes.

' Since certain changes may be made in the above products, compositions and processes without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a'limiting sense.

What is claimed'is: 1. A compound ofthe formula: J

radical; .m. is one of the positive integers 1 and 2; Z is an arylene group having the carbon atom'of said directly attached to a first cyclic carbon atom and a first nitrogen atom or" said N=N group directly attached to a second cyclic carbon atom, said arylene group selected from the group consisting of arylene'groups of the benzene and naphthalene series; Ar is'a monovalent cyclic group having a second nitrogen ato-mof said N=N group directly attached to a cyclic carbon atom, said cyclic group selected from the group consisting of cyclic groups of the benzene, naphthalene and pyrazolone series; and one of said Z and Ar groups containing a group selected from the group consisting of hydroxyl and amino groups filed July 14, 1958 (now abandoned) claims the photodirectly attached to a cyclic carobn atom in one of the ortho and para positions with respect to said N=N group.

2. 2-(4-[ 4'f-(2",5"' dihydroxyphenethyl) phenylcarbamyl] -phenylazo -4-methoxy-1-naphthol.

3. 1-(2',5f-dirnethoxyphcnylazo) 3 (2,5-dihydroxyphenylcar-bamyl -2-naphthol. V

4. 1-( 4-benzamido-2,5-diethoxy) phenylazo-3-(2,5- dihydroxyphenylcarbamyl)-2-naphthol.

No references cited.

' CHARLES E. PARKER, Primary Examiner. 

1. A COMPOUND OF THE FORMULA: 